Maternal breast carcinoma metastases to the placenta: a case report and literature review

Abstract

Pregnancy associated with malignancy and placental metastasis is uncommon. Seventy-three cases of placental metastases have been reported in the English literature. The most common pla-cental metastases are from melanoma, followed by haematologi-cal malignancies. We report a case of maternal breast malignancy with placental micrometastasis despite an unremarkable gross placental appearance in a 42-year-old Chinese lady. She was diagnosed with infiltrating ductal carcinoma grade 3 in 2007 and underwent surgery and chemoradiation. She presented recently with an unplanned pregnancy and opted for termination of pregnancy. The placenta was grossly normal. However, microscopy revealed infiltration of chorionic villi by malignant epithelial cells which were immunopositive for ER and PR; negative for b-hCG, S-100protein and HMB-45. The amniotic membranes, umbilical cord and major fetal organs were unremarkable. This case highlights the importance of examination of the placenta in maternal malignancies, as findings have a bearing on management of the patient and newborn (in the case of term pregnancy). Other than microscopy for the presence of malignant cells in the inter-villous space, one needs to scrutinise for malignant villous invasion which is associated with fetal metastasis. This warrants closer and longer follow-up for the infant to detect systemic involvement by malignancy. Pregnancy associated with malignancy and placental metastasis is uncommon. Seventy-three cases of placental metastases have been reported in the English literature. The most common pla-cental metastases are from melanoma, followed by haematologi-cal malignancies. We report a case of maternal breast malignancy with placental micrometastasis despite an unremarkable gross placental appearance in a 42-year-old Chinese lady. She was diagnosed with infiltrating ductal carcinoma grade 3 in 2007 and underwent surgery and chemoradiation. She presented recently with an unplanned pregnancy and opted for termination of pregnancy. The placenta was grossly normal. However, microscopy revealed infiltration of chorionic villi by malignant epithelial cells which were immunopositive for ER and PR; negative for b-hCG, S-100protein and HMB-45. The amniotic membranes, umbilical cord and major fetal organs were unremarkable. This case highlights the importance of examination of the placenta in maternal malignancies, as findings have a bearing on management of the patient and newborn (in the case of term pregnancy). Other than microscopy for the presence of malignant cells in the inter-villous space, one needs to scrutinise for malignant villous invasion which is associated with fetal metastasis. This warrants closer and longer follow-up for the infant to detect systemic involvement by malignancy.